CA1145416A - Portable electronics repair system including improved desolderer for use therewith - Google Patents
Portable electronics repair system including improved desolderer for use therewithInfo
- Publication number
- CA1145416A CA1145416A CA000352033A CA352033A CA1145416A CA 1145416 A CA1145416 A CA 1145416A CA 000352033 A CA000352033 A CA 000352033A CA 352033 A CA352033 A CA 352033A CA 1145416 A CA1145416 A CA 1145416A
- Authority
- CA
- Canada
- Prior art keywords
- desolderer
- heating wire
- seal
- tip
- handle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Abstract
ABSTRACT OF THE DISCLOSURE
A portable electronics repair system including a portable container, a motor disposed within the container, and air/vacuum pump disposed within the container and driven by the motor, an electrical power source removably connected to the container for driving the motor, and a desolderer removably connected to the air/vacuum pump, the disolderer including an electrical heater assembly energized by the electrical power source.
The desolderer includes a high heat, low energy consumption heater assembly and desoldering tip combination which facili-tates rapid heating of the tip to soldering melting temperatures.
An improved heater assembly is also provided which may be removably connected to the desolderer handle. the solder col-lector tube may be disposed within the desolderer handle and mounted with respect to an outer sleeve of the heater assembly.
Means are provided for connecting the heating wire to the space outside the solder collector tube. Means are also provided for removably connecting the desoldering tip within the heater assembly. A removably rear housing including flexible gripping members is mounted at the rear of the desolderer handle.
A portable electronics repair system including a portable container, a motor disposed within the container, and air/vacuum pump disposed within the container and driven by the motor, an electrical power source removably connected to the container for driving the motor, and a desolderer removably connected to the air/vacuum pump, the disolderer including an electrical heater assembly energized by the electrical power source.
The desolderer includes a high heat, low energy consumption heater assembly and desoldering tip combination which facili-tates rapid heating of the tip to soldering melting temperatures.
An improved heater assembly is also provided which may be removably connected to the desolderer handle. the solder col-lector tube may be disposed within the desolderer handle and mounted with respect to an outer sleeve of the heater assembly.
Means are provided for connecting the heating wire to the space outside the solder collector tube. Means are also provided for removably connecting the desoldering tip within the heater assembly. A removably rear housing including flexible gripping members is mounted at the rear of the desolderer handle.
Description
~s~6 ; ~, BACKGROUND OF THE INVENTION
1. Field o the Inventlon Thîs in~ention relates to po table systems ~or repairing electronic c~rcuitry including p~in~ed circuits and the like and to desolderers for use in such systems and other similar systems.
1. Field o the Inventlon Thîs in~ention relates to po table systems ~or repairing electronic c~rcuitry including p~in~ed circuits and the like and to desolderers for use in such systems and other similar systems.
2. Discussion QL the Prior Art _ _ !
There are presently various repair systems on the market for the repair of electronic sysJ~ems. These range the gamut from a simple soldering iron permitting soldering of components to complex systems allowing desoldering, thermal strippin~, resist soldering and desoldering, thermal parting, reflow soldering, conductive tweeze heating systems, chemical plating, as well as minature ~achining systems ~or abrading, milling, drilling, etc.
These total systems typica].ly are made up in a modular package, consisting of a power source, motor, vacuum pump, heating elements for soldering, desoldering, as well as con-ductive and resistive heating devices and transformers to either transform the mains voltage to a wor~ing voltage for high current and low voltage application, as well as rectification to direct current in the case of chemical plating operations.
Typically, these repair systems weigh as lit~le as 13 lbs.
(without tools) and weigh as much as 40 lbs. or more for the larger systems. They all have certain basic limitations: (a) heavy weight; (b) they require line voltage; (c) they cannot be readily carri.ed; (d) they cannot be readily used in installa- !
tions where line voltage is not available; (e) they use large . I, . . I
. ~ ~.
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amounts of energy; (f) their cost is relatively high, thus precluding their use by a wide range of service technicians, such as T.V. repairmen, telephone li~lemen, etc.; and (g) they pose certain potential hazards to both personnel operating the same, as well as to the devices worked upon, because of t'ne high voltages used during operation.
Within recent years there have been various devices on the market which provide a vacuum source without a vacuum pump by means of Venturi systems and the use of compressed air, either through shop air or cor,1pressed air cylinders or cartridges. While this eliminates the need for line voltage, I
t does not address the problem of providing electrical energy for the various resistive or inductive devices re~uired for the repair of electronic systems.
In the past, some work has been done to provide low voltage devices. For example, there are battery-operated soldering irons, as well as low voltage operated vacuum pumps, and low voltage ~C and DC motors. However, all of these battery~operated devices have very limited operating life. While recharge capability usually exists, it again requires line voltage via a charger. Most of these battery-operated devices operate on either 1.2 or 2.4 volts, thereby precluding their use for those applications where a 12 VDC system might be readily available, e.g., mobile repair trucks, cigarette lighter outlet on most automobiles and trucks. Similarly, these devices typically have one, two or more batteries mounted within.
This often results in a rather u~wieldy apparatus, which is relatively heavy, resulting in an awkward tip to grip ratio, making precise handling of the tool very aif~icult.
_3_ ~ 5~6 SUI~M~RY OF TIIE INVENTION
It is thus a prlmary object of this invention to provide a portable electronics repair sys~em having an improved de-solderer.
It is a further object of this invention to provide an improved desolderer having one or more of the following features:
(a) optimized tip to yrip ratio, (b) a quick connect, removable solder and solder collecting chamber and sealing system, (c) a high heat, low energy consumpLion heater assembly and desoldering tip combination, (d) an improved removable tip, and (e) improved means for connecting the heater wires to the space outside the solder collecting chamber when the chamber is mounted with respect to an outer sleeve of the heater assembly.
Other obiects and advantages of this invention will be apparent from a reading of the following specification and claims take ith the drawin5.
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BRIEF DESCRIPTIOM OF THE DRAWING
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Figure 1 is a block diagr.am OL an illustrative portable electronics repair system in accordance with the invention.
Figures 2 and 2A are respective plan and front views o~ an illustrative portable repair pack for use in the system of Figure 1.
Figure 3 is a partial cross-sectional view of an illus-. trative desolderer hand-piece for use in the system of Figure 1.
Figure 4.is a perspective view of a.desoldering tip for use with the desolderer of Figure 3.
Figure 5 is a cross-sectional view of a modified desolder-ing tip for use with the desolderer of Figure 3.
Figures 6-8 are respective cross-sectional views on the . lines 6-6, 7-7 and 8-8 of Figure 3.
Figure 9 is an end view of the desolderer of Figure 3.
Figure 10 is a cross-sectional view of an illustrative 1 air/vacuum pu~mp for use in the system o Figure 1.
: Figures 11 and 12 are respective cross-sectional views take~ on the lines 11-11 and 12-12 of Figure 10.
:. 20 Figures 13 and 14 are cross-sectional views of illustra-tive filter holding members for use with the system of Figure 1.
.. Figure 15 is a cross-sectional view illustrating members Figures 13 and 14 when assembled.
Figure :L6 is a schematic diagram of an illustrative battery status/tem~erature controller circuitry for use with the system of Figure 1.
Figure 17 is a schematic diagram of an illustrative, modiied battery status indicating circuitry or use with the system of Figure 1.
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DETAILED DESCRIPTION OF THE PREFERRED EM~ODIMENTS
. _ .
OF THE IWVENTION
Referring to ~igure 1, there is shown an illustrative portable electronics repair system in accordance with the invention whéreby a desolderer/solderer 10, which will here-inafter be referred to as a desolderer, or the like is con- ¦
nected to a power source 12 via temperature control/battery status circuitry 14 and to a vacuum/pressure pump 16, which is driven by a motor 18. Motor 18 may also drive other optional devices such as a micro-drill 20 via a double ended shaft or another motor might be employed for this purpose. Power source 12 is preferably a 12 volt source, which may be derived from (a) alternating line current voltage 22 which is trans- ¦
formed and rectified to 12 volts by transformer~rectifier 24, (b) a 24/32 volt DC source 26, the output of which is applied either to a voltage divider 28 or a DC to DC converter 30 to obtain the 12 volts, (c) a 12 volt DC power supPly 32 such as an automoblle battery 34, ~d) a non-rechargeable battery 36 or ~e) a rechargeable battery 38 having an associated battery charger 40 where battery 38 is preferably a lead acid sealed battery or a plurality of such batteries connected in series.
. Referring to Figures 2 and 2A, there are shown respective plan and front views o~ an illustrativ~ portable repair pack generally indicated at 42. The pack ~referablv comprises two containers 44 and 46 which are removably connected to one another by appropriate means. Disposed within container 46 is power supply 12. Jacks 48 and 50 are provided at one end ....
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ll6 of container 46. Pins 52 and 54 removably enyage ~he jacks so that the desired 12 volts appears across terminals 56 and 58 where the terminals are disposed at one end of container 44.
Also disposed within container 44 is motor 18, pump 16, tempera-ture control/battery status circuit 14 together with a filter generally indicated at 60. A switch 62 for energizing c r- ¦
cuitry 14 is provided on the forward wall of container 44 as is an LED 64 which provides an indication of the battery status.
Connections 66 and 68 are provided on a side wall of container 44 whereby either vacuum (via connector 68) or pressure (via connector 66) may be applied to desolderer 10. The normal mode of operation is vacuum. Thus, a porous muffler 70 may be pro- I
vided on connector 66. A hose 72 is normally connected to connector 68 and thence to desolderer 10. When air under pressure is to be applied to the desolderer, the positions of muffler 70 and hose 72 are reversed.
Flectrical connections to the desolderer pass through a restrainer 74 disposed in a wall o container 44. Thus, it can be seen repair pac~ 42 contains a number of componenks necessary for a sophis~icated repair system, yet the size and packaging of these components is such that the pack is readily portable. The interconnection of these components within the pack will be described in more detail hereinafter.
Referring to Figure 3, there is shown in partial cross~
section an illustrative desolderer 10 for use with the portable electronics repair system of the present invention. Generally, the desolderer includes a tip 78, a heater assembly 8G, a handle 82, a solder:collection chamber 84 disposed within the handle, and a spring loaded rear housing 86.
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The heater assemb1y 80 includes a bobbin 87 which prefera~ly integrally incorporates at the forward end thereof a sleeve 88 althou~h the sleeve need not necessarily be integrally con-nected to the bobbin. Sleeve 88 preferably has a groove 90 provided in the inner surface thereof. Replaceable tubular tip 78 may have a ring 92 disposed about the periphery thereof so that ring 92 may be normally removably disposed within groove 90 to thereby hold tip 78 in place with respect to heater assembly 80. As can be seen in Figures 3 and 4, sleeve 88 is preferably provided with three equally spaced slots 94 which permit the sleeve to expand as ring 92 is inserted into the sleeve. Thus, the tip 78 may be readily removed from heater assembly 80. Further, ring 92 may assist in the sealing or vacuum.
In Figure 5, an alternative arrangement for mounting tip 78 with respect to heater assembly 80 is illustrated wherein sleeve 88 is provided with an internally threaded hole 96 and a set screw 98 which holds the tip 78 in place. Further, sleeve 88 may be counterbored as indicated at 100 to receive ring 92 of tip 78. Hence, the ring 92 serves both to position the tip with respect to the heater assembly and also to act as a vacuum seal. In order to mount ring 92 on tip 78, a circumfere~tial groove 93 inay be formed on the tip and a metal music wire ri.ng or the like may be inserted within the groove.
The heater assembly further includes a preferably insulating, outer cylindrical sleeve 102 which is preferably made of a plastic, heat insulating material such as that sold under the trademark Vespel by Dupont Co. As can be seen in Figures 3 1. ~ .
il ` ~8-., ~454~6 and 6, a rectangular ~lange 106 is provided at the rearward end of sleeve 102.~ Annular front and rear spacers 104 and 108 are provided between sleeve 102 and bobbin 87, these spacers preferably being made of heat insulating material such as ceramic. Disposed within sleeve 102 is heating wire or element 110 which preferably comprises an alloyed material such as nickel-iron which has a relatively large coefficient of re- ¦
sistance as will be explained in more detail hereinafter with respect to Figure 16. From the foregoing, it can be seen that sle~ve 102, bobbin 87 and spacers 104 and 108 advantageously define an enclosed space for heating wire 110 where the spacer may be radial struts but which preferably are ring-like to completely enclose the heating wire space.
The heating wire is preferably wound about bobbin 87, the bobbin preferably comprising a low mass, heat conductive, corrosion resistant material such as that sold under the trade-mark EverDur. Disposed between the bobbin and heating wire 110 is a layer of electrical insulating material such as mica, the layer being indicated at 112. Also preferably disposed over the heating wire is a layer 113 of insulating material, which lessens the amount of outwardly radiated heat.
The tip 78 thus preferably extends completely through the bobbin 87, the tip illustratively comprising ~ickel plated copper. 'rhe heat capacities (or masses) of the bobbin and tip are such that the entire tip 78 may be quickly brought up to temperature due to the r~latively low combined mass of the bobbin and tip. Preferably, the time required to heat the entire tip ~ a solder melting temperature is 1:BS than 90 ' _g_ ' .
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seconds although it may be as much as five minut~s and is typically more than 30 seconds although it may be less. Hence, the desolderer is particularly well suited for portable applica-tions.
The heat capacities (or masses) of khe bobbin and tip are in large part reduced because of the low heat capacity (or mass) of the bobbin compared to the heat capacity (or mass) of prior art bobbins such as that disclosed in ~.S. Patent
There are presently various repair systems on the market for the repair of electronic sysJ~ems. These range the gamut from a simple soldering iron permitting soldering of components to complex systems allowing desoldering, thermal strippin~, resist soldering and desoldering, thermal parting, reflow soldering, conductive tweeze heating systems, chemical plating, as well as minature ~achining systems ~or abrading, milling, drilling, etc.
These total systems typica].ly are made up in a modular package, consisting of a power source, motor, vacuum pump, heating elements for soldering, desoldering, as well as con-ductive and resistive heating devices and transformers to either transform the mains voltage to a wor~ing voltage for high current and low voltage application, as well as rectification to direct current in the case of chemical plating operations.
Typically, these repair systems weigh as lit~le as 13 lbs.
(without tools) and weigh as much as 40 lbs. or more for the larger systems. They all have certain basic limitations: (a) heavy weight; (b) they require line voltage; (c) they cannot be readily carri.ed; (d) they cannot be readily used in installa- !
tions where line voltage is not available; (e) they use large . I, . . I
. ~ ~.
~ 5fl3~
ll I .
amounts of energy; (f) their cost is relatively high, thus precluding their use by a wide range of service technicians, such as T.V. repairmen, telephone li~lemen, etc.; and (g) they pose certain potential hazards to both personnel operating the same, as well as to the devices worked upon, because of t'ne high voltages used during operation.
Within recent years there have been various devices on the market which provide a vacuum source without a vacuum pump by means of Venturi systems and the use of compressed air, either through shop air or cor,1pressed air cylinders or cartridges. While this eliminates the need for line voltage, I
t does not address the problem of providing electrical energy for the various resistive or inductive devices re~uired for the repair of electronic systems.
In the past, some work has been done to provide low voltage devices. For example, there are battery-operated soldering irons, as well as low voltage operated vacuum pumps, and low voltage ~C and DC motors. However, all of these battery~operated devices have very limited operating life. While recharge capability usually exists, it again requires line voltage via a charger. Most of these battery-operated devices operate on either 1.2 or 2.4 volts, thereby precluding their use for those applications where a 12 VDC system might be readily available, e.g., mobile repair trucks, cigarette lighter outlet on most automobiles and trucks. Similarly, these devices typically have one, two or more batteries mounted within.
This often results in a rather u~wieldy apparatus, which is relatively heavy, resulting in an awkward tip to grip ratio, making precise handling of the tool very aif~icult.
_3_ ~ 5~6 SUI~M~RY OF TIIE INVENTION
It is thus a prlmary object of this invention to provide a portable electronics repair sys~em having an improved de-solderer.
It is a further object of this invention to provide an improved desolderer having one or more of the following features:
(a) optimized tip to yrip ratio, (b) a quick connect, removable solder and solder collecting chamber and sealing system, (c) a high heat, low energy consumpLion heater assembly and desoldering tip combination, (d) an improved removable tip, and (e) improved means for connecting the heater wires to the space outside the solder collecting chamber when the chamber is mounted with respect to an outer sleeve of the heater assembly.
Other obiects and advantages of this invention will be apparent from a reading of the following specification and claims take ith the drawin5.
. , ' ,'' ' , . . ~ 11 '' !
l l ~ ~ _4_ ~: . 1, ' .
~5~
J
BRIEF DESCRIPTIOM OF THE DRAWING
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Figure 1 is a block diagr.am OL an illustrative portable electronics repair system in accordance with the invention.
Figures 2 and 2A are respective plan and front views o~ an illustrative portable repair pack for use in the system of Figure 1.
Figure 3 is a partial cross-sectional view of an illus-. trative desolderer hand-piece for use in the system of Figure 1.
Figure 4.is a perspective view of a.desoldering tip for use with the desolderer of Figure 3.
Figure 5 is a cross-sectional view of a modified desolder-ing tip for use with the desolderer of Figure 3.
Figures 6-8 are respective cross-sectional views on the . lines 6-6, 7-7 and 8-8 of Figure 3.
Figure 9 is an end view of the desolderer of Figure 3.
Figure 10 is a cross-sectional view of an illustrative 1 air/vacuum pu~mp for use in the system o Figure 1.
: Figures 11 and 12 are respective cross-sectional views take~ on the lines 11-11 and 12-12 of Figure 10.
:. 20 Figures 13 and 14 are cross-sectional views of illustra-tive filter holding members for use with the system of Figure 1.
.. Figure 15 is a cross-sectional view illustrating members Figures 13 and 14 when assembled.
Figure :L6 is a schematic diagram of an illustrative battery status/tem~erature controller circuitry for use with the system of Figure 1.
Figure 17 is a schematic diagram of an illustrative, modiied battery status indicating circuitry or use with the system of Figure 1.
.
~ 4~ 1 . ,~.
DETAILED DESCRIPTION OF THE PREFERRED EM~ODIMENTS
. _ .
OF THE IWVENTION
Referring to ~igure 1, there is shown an illustrative portable electronics repair system in accordance with the invention whéreby a desolderer/solderer 10, which will here-inafter be referred to as a desolderer, or the like is con- ¦
nected to a power source 12 via temperature control/battery status circuitry 14 and to a vacuum/pressure pump 16, which is driven by a motor 18. Motor 18 may also drive other optional devices such as a micro-drill 20 via a double ended shaft or another motor might be employed for this purpose. Power source 12 is preferably a 12 volt source, which may be derived from (a) alternating line current voltage 22 which is trans- ¦
formed and rectified to 12 volts by transformer~rectifier 24, (b) a 24/32 volt DC source 26, the output of which is applied either to a voltage divider 28 or a DC to DC converter 30 to obtain the 12 volts, (c) a 12 volt DC power supPly 32 such as an automoblle battery 34, ~d) a non-rechargeable battery 36 or ~e) a rechargeable battery 38 having an associated battery charger 40 where battery 38 is preferably a lead acid sealed battery or a plurality of such batteries connected in series.
. Referring to Figures 2 and 2A, there are shown respective plan and front views o~ an illustrativ~ portable repair pack generally indicated at 42. The pack ~referablv comprises two containers 44 and 46 which are removably connected to one another by appropriate means. Disposed within container 46 is power supply 12. Jacks 48 and 50 are provided at one end ....
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ll6 of container 46. Pins 52 and 54 removably enyage ~he jacks so that the desired 12 volts appears across terminals 56 and 58 where the terminals are disposed at one end of container 44.
Also disposed within container 44 is motor 18, pump 16, tempera-ture control/battery status circuit 14 together with a filter generally indicated at 60. A switch 62 for energizing c r- ¦
cuitry 14 is provided on the forward wall of container 44 as is an LED 64 which provides an indication of the battery status.
Connections 66 and 68 are provided on a side wall of container 44 whereby either vacuum (via connector 68) or pressure (via connector 66) may be applied to desolderer 10. The normal mode of operation is vacuum. Thus, a porous muffler 70 may be pro- I
vided on connector 66. A hose 72 is normally connected to connector 68 and thence to desolderer 10. When air under pressure is to be applied to the desolderer, the positions of muffler 70 and hose 72 are reversed.
Flectrical connections to the desolderer pass through a restrainer 74 disposed in a wall o container 44. Thus, it can be seen repair pac~ 42 contains a number of componenks necessary for a sophis~icated repair system, yet the size and packaging of these components is such that the pack is readily portable. The interconnection of these components within the pack will be described in more detail hereinafter.
Referring to Figure 3, there is shown in partial cross~
section an illustrative desolderer 10 for use with the portable electronics repair system of the present invention. Generally, the desolderer includes a tip 78, a heater assembly 8G, a handle 82, a solder:collection chamber 84 disposed within the handle, and a spring loaded rear housing 86.
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The heater assemb1y 80 includes a bobbin 87 which prefera~ly integrally incorporates at the forward end thereof a sleeve 88 althou~h the sleeve need not necessarily be integrally con-nected to the bobbin. Sleeve 88 preferably has a groove 90 provided in the inner surface thereof. Replaceable tubular tip 78 may have a ring 92 disposed about the periphery thereof so that ring 92 may be normally removably disposed within groove 90 to thereby hold tip 78 in place with respect to heater assembly 80. As can be seen in Figures 3 and 4, sleeve 88 is preferably provided with three equally spaced slots 94 which permit the sleeve to expand as ring 92 is inserted into the sleeve. Thus, the tip 78 may be readily removed from heater assembly 80. Further, ring 92 may assist in the sealing or vacuum.
In Figure 5, an alternative arrangement for mounting tip 78 with respect to heater assembly 80 is illustrated wherein sleeve 88 is provided with an internally threaded hole 96 and a set screw 98 which holds the tip 78 in place. Further, sleeve 88 may be counterbored as indicated at 100 to receive ring 92 of tip 78. Hence, the ring 92 serves both to position the tip with respect to the heater assembly and also to act as a vacuum seal. In order to mount ring 92 on tip 78, a circumfere~tial groove 93 inay be formed on the tip and a metal music wire ri.ng or the like may be inserted within the groove.
The heater assembly further includes a preferably insulating, outer cylindrical sleeve 102 which is preferably made of a plastic, heat insulating material such as that sold under the trademark Vespel by Dupont Co. As can be seen in Figures 3 1. ~ .
il ` ~8-., ~454~6 and 6, a rectangular ~lange 106 is provided at the rearward end of sleeve 102.~ Annular front and rear spacers 104 and 108 are provided between sleeve 102 and bobbin 87, these spacers preferably being made of heat insulating material such as ceramic. Disposed within sleeve 102 is heating wire or element 110 which preferably comprises an alloyed material such as nickel-iron which has a relatively large coefficient of re- ¦
sistance as will be explained in more detail hereinafter with respect to Figure 16. From the foregoing, it can be seen that sle~ve 102, bobbin 87 and spacers 104 and 108 advantageously define an enclosed space for heating wire 110 where the spacer may be radial struts but which preferably are ring-like to completely enclose the heating wire space.
The heating wire is preferably wound about bobbin 87, the bobbin preferably comprising a low mass, heat conductive, corrosion resistant material such as that sold under the trade-mark EverDur. Disposed between the bobbin and heating wire 110 is a layer of electrical insulating material such as mica, the layer being indicated at 112. Also preferably disposed over the heating wire is a layer 113 of insulating material, which lessens the amount of outwardly radiated heat.
The tip 78 thus preferably extends completely through the bobbin 87, the tip illustratively comprising ~ickel plated copper. 'rhe heat capacities (or masses) of the bobbin and tip are such that the entire tip 78 may be quickly brought up to temperature due to the r~latively low combined mass of the bobbin and tip. Preferably, the time required to heat the entire tip ~ a solder melting temperature is 1:BS than 90 ' _g_ ' .
., ' - \
~4S~lG
seconds although it may be as much as five minut~s and is typically more than 30 seconds although it may be less. Hence, the desolderer is particularly well suited for portable applica-tions.
The heat capacities (or masses) of khe bobbin and tip are in large part reduced because of the low heat capacity (or mass) of the bobbin compared to the heat capacity (or mass) of prior art bobbins such as that disclosed in ~.S. Patent
3,392,897 granted to William J. Siegel.
The desolderer described in this patent is suitable for many applications. However, where portability of repair equipment is desirable, the desolderlng tip should preferably be-quickly raised to the required desoldering temper- ¦
ature. ~owever, the available power supply may be relatively small ~a 12 volt battery, for example) so that the temperature can not be quickly raised by power alone. Also, there are other considerations which preclude the use of power alone to quickly raise the tip temperature. In any event, the efficiency of the desolderer in converting electrical energy to heat s~ould also be improved to permit the more efficient utilization of a smaller power supply.
Thus, for the above reasons, it is desirable that the ratio o~ the hea~ capacities ~or masses) of bobbin 87 and tip 78 be substantially less than that employed in U. S. Patent 3,392,897.
Generally, the heat capacity (or mass) of the bobbin should not be more than approximately twice that of the tip~
.1 The rea:rward portion of bobbin 87 is preferably outwardly I bent as indiaated at 114 to thereby mechanically hold the heater assembly together and to also assist in the sealing o~ the vacuum.
,' ' ' -10-, . I
~1~5~16 The forward end 117 of handle 82 is èxternally threaded at 118. An internally threaded cap 120 is threaded onto threads 118 to removably secure the flange 106 of heater assembly 80 to handle 82. Thus, due to the removable connection of the heater assembly to the handle, the heater assembly can be readily removed for repair or replacement. The forward end 117 of handle 82 is rectangularly slotted at 122 as indicated in Figure 6 to receive the rectangular flange 106 of heater assembly 80 in mating engagement. Hence, the heater assembly is non-rotatably mounted with respect to the handle 82.
The opposite ends of heating wire 110 are connected to flat electrical contacts 124 (typically nickel), which may pass between flanges 106 and spacer 108, there preferably being pro~ i l vided channels on the inner surfaces of the flanges to facili-1 15 tate tha passage of the contacts between the flanges and the spacer. The contacts 124 are then bent against the rear faces of flanges 124 and finally are bent once again into holes 125 in the rear faces to secure them in place.
Contacts 124 engage contacts 126 (beryllium, for e~ample) provided at the forward end of handle 82, which contacts may be J-shaped to provide some springiness and thus intimate contact I with contacts 124. The forward end 117 of the handle may be provid~d with slots into which contacts 126 may be inserted and held in place, the contacts 126 terminating at 128.
The forward end of solder collec~ion chamber 84 is pressed against a flexible seal 146 disposed within forward end 117 of the handle. The seal 146 intimately fits over contacts124 to provide an hermetic seal at the points where the contacts pass to the space outside solder collection chamber 84. In this connection, it.shouId be noted the forward end of solder collec-tion chamber.84.is effectively connected to sleeve 102 via seal 146 and flange 106.. Hence, the foregoing arrangement provides a novel and advantageous technique or connecting the heater wires to the space outs:Lde cham~er 84 when the chamber is mounted with respect to a sleeve (sleeve 102) which contains the heater wires. Xence, thermal isolation of seal 146 rom tip 78 is enhanced thereby promoting seal performance and longevity. ~lso, by moving annular rear spacer 108 to the right in Figure 3, the thermal isolation of the seal can be furthcr enhanced.
It should also be noted with respect to seal 146 that not only does one.side thereof seal the connection of the heater wires.to the outside of chamber 84, but the other side ~hereof . seals the forward end of the cha~.~er. Hence, the seal is doubly effective in maintaining the requisite vacuum space withir.
1 the desolderer. .
i Wires 130 are connected to points 128, the wires passing , 20 through a cable 132 back to porta~le power pack 42 of Figure .~ 2. A light emitting diode 134 mounted on handle 82 is con-nected across wires 130, the purpose of which is to in-. dicate to the operator that the desolderer ls ready for . use as will be described i~ more detail hereinafter with respect to Figure 16.
Also extending through cable 132 are wires 136 which engaSe .1 ' . . . ' . , ' 'i ~ 12- ' ,' .. , ''.
.. .. ..
~5~6 ..
flexible contact 138 and contact 140, as can be seen in Figure 3.
A push button 142 engages flexible contact 138 and is normally outwardly biased by a spring 144. Upon depression of spring 142, contacts 138 and 140 are closed to apply vacuum or pressure to the desolderer as indicated in Figure 2. As can be seen in Figures 3 and 7, a plurality of ribs 148 depending from the inner surface of handle 82 center and support solder collec-tion chamber 84.. As can also be seen in Figure 7, handle 82 , is provided with a hollow ridge 150 which provides for the mounting of LED 134, switch 142, contacts 138 and 140 and 1. which provides a passageway for wires 130 and 136.
I . As stated above, collection chamber 84 is pressed against . forward seal 146. This is effected by a spring loaded rear . housing 86, as can best be seen in Figures 3, 8 and 9. This housing comprises an air/vacuum tube 152, the rearward end of which has hose 72 disposed thereover and the forward end of which has a helical baffle 154 connected thereto by means of . a set screw 156. A hole 158 extends through ~he tube from hose 72 to an opening 160 extending through the side of the tube. Thus, an air/vacuum path is established ~rom the interior . of chamber 84 to hose 72. Tube 152 is mounted with respect to chamber 84 via a cup-shaped seal 162 having a forward portion 164 which extends into chamber 84 to provide an air-tight seal and an enlarged rear portion 166 which fits over the end ~ ~of chamber 8 A ring 168 may be provided OA the outer .1 . I
., Y13-' ' !' i ~4~ 6 . circumference of tube 152 to position the tube with respect to seal 162. , Slidably disposed on tube 152 is a detenting pinch lock 170, the purpose o which is to hold chamber 84 in place within handle 82 in a press fit against forward seal 146. The locX
170 is generally H-shaped and includes a cylindrical bearing . hub 172 which is slidably disposed on tube 152. Extending from hub 172 are a pair of flexible support arms 174 which . support a pair o flexible, gripping fingers 176, The forward ends of ~ingers 176 are provided with detents 178. A com-pression spring 180 is mounted around tube 152 between the rearward portion 166 of seal 162 and arms 174 of lock 170.
Thus, the lock is normally biased away from the rearward end of chamber 84. A ring 182 mounted on tube 152 limits the rear ward movement of lock 170.
In order to pro~ide a gripping surface for detents 178 of lock 170, ,a pair of openings 184.are provided in the sides of handle 82., The rear edge 186 of these openings provides the requisite-gripping surface. Also, as can best be seen in Figures 8 and 9, a pair of lands 188 are provided on the rear- If ward surface of handle 82 to provide a pair of recesses upon l, which the fingers 176 may be mounted. 1, ~he~ the spri~g loaded rear housing 86 is in the position ~ shown in Fi~ures.3 and 8, the solder collection chamber 84 is locked into position within the handle 82 and is ready for operation. Assuming the heater has been en~rg;ze~, the o~er~or ne~d only ~ress b~tton 142 whereby vacuum may be applied to tip 78, to withdra~ molten solder through tip 78 into solder ~ 6 collection chamber 84 where it splatters against helical baffle 154. Due to the helica.l shape of the ba,fle and due to the placement of vacuum port 156 on the side of tube 152, there is little, i any, probability o the molten solder entering the por~. After a number of operations, it will be-come necessary to clean chamber 84 of the molten solder col- ¦
lected therein. This is simply effected by pinching the fingers 176 of lock 170 to the dotted line positions shown in Figure . 8. Once the detents 178 are removed fxom edges 186 of openings 184, spring 180 will push lock 170 back to stop 182. Thus, the entire assembly including spring loaded rear housing 86 and solder collection chamber 84 may be removed from the open rearward end of handle 82. Once this is done, the seal 162 may be removed from chamber 84 thereby removing the entixe rear housing 86 from the chamber. As the housing is removed from the chamber, it may be rotated by the operator to thereby scrape the inner surface of chamber 84 with the edges of the helical baffle 154 and thus scrape ~he surface clean of any solder solidified thereon. To expedite this, the radial extent-of the baffle .154 substantially corresponds to that of the inside diameter of collection chamber 84 as can be seen in Figures 3 and 8.
Once the cham~ber has been cleaned, it can again be mounted on the forward portion 164 of seal 162. The entire assembly is then inserted into the handle with the lock 170 being pinched to its.dotted position as shown in Figure 8. The assembly including rear housing 86 and chamber 84 is then pressed against spring 180 until detents 178 can b~ detented over 1 ~ 54~
the edges 186. At this time the lock 170 is released to thereb~
once again lock the collection chamber 84 in place within handle 82 and press fit the forward end of the chamber against forward seal 146 and thus, effect an air-tight seal at this end of the charber. It should be noted from the above that rear housing 86 is advantageously moved straight in and out when it is attached and disconnected from the handle. Further, in Figure 9 ribs 1~8 are also provided at the rearward end of handle 82 to provide additional centering support for the chamber within the handle.
Also the rearward end of handle 82 is open as indicated at 183 in Figures 3 and 9 to provide air venting thxough opening 183 and side openings 184 to thereby promote heat dissipa~ion from solder collection chamber 84.
Referring now to Figures 10-12, there is shown an illus-1~ trative vacuum pump in accordance with the invention. Motor 18 for driving pump 16 is commercially available, it typically being a 12 volt DC motor which is available, for example, from the Pittman Company, ~arleys-~ille, Penna. The drive shaft 190 has mounted thereon a rotor 192, the shaft being provided with a key-194 which engageR a slot 196 within the rotor. The rotor-can ~e powdered metal or extruded or molded plastic.
Provided within the xotor are four slots which slidably receive four vanes 198. The vanes may be made from a lower cost phenolic or carbon. A rotor housing 200 is eccentrically mounted with respect to rotor 192, the housing being mounted via screws 202 to a plate 204 non-rotatably mounted onto ro~or 18. A rotor end plate 206 is disposed between the housing 200 and plate 204. Recesses 208 are provided in housing 200 so that the heads of screws 202 are recessed within the housing.
A further rotor end plate 210 is disposed between housing 200 ~ !'.7!r~
~.:3 45~16 and a plate 212. Plate 212 is secured to plate 204 via screws 214 to thereby,hold the pump together.
.As can be seen in Figure 11, the inner surace of housing 200 is provided with an elongat:ed indentation 216 at the edge thereof,adjacent end plate 210. Further, the inner surface is also provided with a further indentation 218 which is also adjacent the end plate 210. Thus, when the rotor is rotated in the clockwise direction in Figure 11, the sliding vanes 198 will assume the illustrated positions and will create a vacuum,at indentation 216 and air under pressure at indenta-tion 2,18. As can be seen in Figures 11 and 12, a pair of tubes 220 and 222 are mounted on plate 212 and are in alignment with holes ,224 which extend through plate 212. Further, these holes.are in,alignment with indentations 216 and 218 of the rotor. Hence, vacuum is provided at port 220 and air under pressure at port 222.
..The vacuum/pressure pump of Figures 10-12 in combination with motor 18.has.a number of op'erational and structural ad-vantages. ,Operationally, the pump is run at a speed much higher than would be normally required to ~enerate the vacuum : needed by desolderer 10. In particular, it is typically run at 8,,000 RP~. By running the pump at this high speed, it is : possible to generate the requisite vacuum in spite of the small size of the pump - that is, typically 1~ inches or less in diameter and:l-1/2 inches or less in length. Further,. by running the pump at a high speed, it is not necessary to . accurately ~abricate the pump components to close tolerances.
This~ in tur~ results in a very economical pump and thereby . -17-.
ll ~ 5~6 lessens the overall cos-t of the portable repair system of this invention. Thus, in fabricating the pump, costly and time consuming rotor shi~ing operations are eliminated. Further, the rotor, rotor housing and vanes can be finished ground in S one pass. Also to further reduce assembly time and facllitate 1, field service without special t:ools, the rotor and vanes are self-centered and self-sealed. To compensate for any tendency of housing 200 to heat as the pump is driven at the high speed, housing 200 is preferably provided with a plurality of circumferentially disposed fins 201, which may be formed during the extrusion of ~he housing.
As can be,seen in Figures 2 and 10, hoses 230 and 232 are respectively connected to vacuum and pressure tubes 220 and 222 where hose 232 is connected to connector 66 and hose 230 is connec,ted to one side of filter 60. A hose 234 is con-nected to the other side of filter 60 and at its other end to connector 68., Referring to Fi~ures 13-15,~an illustrative filter 60 is shown. As can be seen in Figure 13, hose 232 is connected to a first cup-shaped member 236 comprising a first part of filter 60 and as can be seen in Figure 14, hose 234 is connected ~o a second cup-shaped member 238. As can be seen in Figure 15, cup-shaped member. 238 is adapted to receive at least one porous ilter 240 and a further ~ilter 242 i~ desired. Further, member 236 is adapted to recelve a gasket 237 and member 238 after the , , latter member has been loaded ~ith filter material. Both members I
236 and 238 are made of flexible material to facilitate the engagement o~,member 238 by member 236. As can be seen in .1 . . Il, ~, . ' . '~
, -18~
., ,,, ~s~
l~
Figures 13 and 15, member 236 is provided with a ci~cumferen~lal ridge 244 at the lower opening 246 thereof which holds member 238 in place`after lt has been inserted within member 236.
To facilitate the engagement of member 238 by member 236, member 238 is~ also provided with an inwardly slanted outer peripheral wall 248.
To re-tain the filters 240 and 242 in place, member 236 is provided with a further circumferential ridge 250 which is so disposed às to engage the filters and hold them in place as indicated in-Figure 15. The flexible material of which the members 236 and 238 are made is preferably a transparent plastic whereby the condition of filters 240 and 242 can be readily observed, as indicated in Figure 2, to thereby ensure filter-replacement when necessary. Due to the two-piece con~
` 15 struction o the filter container 60, member 238 can be readily snapped from member 236, new filters inserted, and snapped back together in an expeditious manner.
Referring to Figure 16, there is shown illustrative temperature`control/ battery status circuitry 14. The cir-cuitry for controlling the heating current to and thus the temperature of heating element 110 of Figure 3 is such that the heating current is supplied at a high rate when the hea~ing element is below a selected temperature and at a very low rate when it is above the selected temperature. The material emplo~ed fox heating element 110 has a positive temperature coefficient of resistance and typically varies from about 1 ohm when cold to`about 4 ohms when the maximum temperature has been reached, alt:hough, o course, other resistance ranges may be ll .' ~454~6 ll utilized. Typically, the heater element material ma~ be a nickel-iron alloy. The circuitry of Figure 16 senses the change in resistance by sensing the change in current through the heating element to thereby control its temperature. A ', digital system as opposed to an analog system is employed to thereby lessen power consumption. Accordingly, pulsed power is continuously applied to element 110 to obtai~ samples of the heater temperature. The sampling is effected by an oscil-lator comprising a comparator 254, a lOK resistor 256, a diode 258, a .027 microfarad capacitor 260 and a voltage divider comprising a 1 megohm resistor 262 and a lOOK resistor 264, it being understood ~he foregoing values are for purposes of illustration.
When heater 110 is raised to its selected temperature, comparator 254 turns off so that its output goes positive.
This allows the capacitor to charge through resistors 262 and 264. As capacitor 260 charges positively, the inverting input of comparator 254 becomes more positive, When it be-comes more positive than the non-inverting input, the outpu~
of comparator 254 goes to ground thereby discharging capacitor 260 through resistor 256 and diode 258, the discharge time being much faster than the charging time.
During the time capacitor 260 is discharging, the output of comparator 254 remains at ground. ~his causes the non-inverting input of a comparator 266 to be at ground while the inverting input thereof is fixed at typically about 4 volts. I
Accordinglyl the output of comparator 266 is grounded. This, ~! in turn, causes a transistor 268 to be cut off. Accordingly, ~I
~20-, ~ . .
~5~16 current flowing through a 200 ohm resistor 270 no longer flows into the base of a transistor 272 where transistors 272 and 274 comprise a Darlinyton pair which supply current to heating element 110.
If the temperature is high enough so that the inverting input to a comparator 276 remains helow the input setting at the non-i~verting input thereof, the sampliny of the heater temperature will last only until capacitor 260 is discharged.
The input settiny at the non-inverting input o comparator 276 may be controlled by a potentiometer 278 or it may be fixed by 27K resistor 280 and 1~ resistor 282. If, as stated above, the temperature is high enough so that the inverting input to comparator 276 remains below the non-inverting input setting, the inverting input of comparator 254 will become ~egative and the output will go positive and capacitor 260 will again start charging positive through resistors 262 and 264. The diode 258 prevents positive charging through resistor 256 on the output o~ comparator 254.
If the temperature is low, the sampling current will ~e high due to the low resistance of heater element 110. Thus, the inverting input of comparator 276 will be more positive than the non-inverting input thereof and the output will be grounded.
This will cau e the non~inverting input o comparator 254 to be more nega~ive and the output of comparatox 254 will stay negative. Hence capacitor 260 will not charge positive as long as the inverting input of comparator 276 is more positive than the non-inverting input.
As the temperature of heating element 110 increases its ~54~
resistance.increases and the current decreases. Eventually, the inverting input of comparator 276 will become negative wit'.
respect to the non-inverting input and the outpuk will move positive. This will allow comparator 254 to switch so that its output will be positive and the capacitor will again charge positive. Also, comparator 266 will switch so that its output will become positive and turn on transistor 268 so that the power pair 272 and .274 are turned off and no current is supplied to heating element 110. After capacitor 260 is charged to thereby switch comparator 254, another sample will occur and the cycle is repeated.
As can be appreciated, the current through heating element 110 is not switched on and of until the current reaches the input setting established at the non-inverting input of com-15 parator 276... Hence, LED 134 of Figures 3 and 16 is not switched on and off until the heating element has been raised to its operating temperature. Accordingly, the operator is notified when the desolderer is ready for use by the blinking on and ofi-of LED 134. Although shown conveniently mounted on the handle of the desolderer in Figure 3, LED 134 can also be mounted on the front panel of the portable power pack shown in Figure 2A.
Other elements employed in the temperature controller circuitry of.Figure 16 are a .1 resistor 28~, 2~ resistor 286, . 200K resistor 288, lOOK resistor 290, comparator 292, lOK
resistor 294,.lOK resistor 296, lOOK resistor 298, lOK resistor 300, diode 302, lOK resistor 304, lOOK resistor 306, lOOK
resistor 308 and 200K resistor 310, it again being understood ~he foregoing.values are given for purposes o~ ill.ustratlon.
.
. -2~- .
.' ~.
~ 5~6 The battery s~atus circuitry of Figure 16 employs a single bulb or package 64 (also see Figure 2) containing two LEDs 314 and 316 which indicate whether the battery voltage is above ~green LED 314 on, red LED 316 off) or ~elow (red ~ED 316 on, green LED 314 off) a certain pre~etermined voltage. The pre-determined voltage is determined by the base to emitter voltage (ON) of two transistors 318 and 320 plus the Zener knee voltage of a Zener diode 322. When the battery voltage is higher ~han the predetermined voltage, a current path is from the positive battery terminal 324 through the emitter-base junction of transistor 318, through Zener diode 322 and 180 ohm resistor 326 into the base of transistor 320 and out its emitter to negative battery terminal 328. Thus, transistors 318 and 320 saturate and a further current path is established b~tween the emitter and collector of transistor 318, through 180 ohm resistor 330-, green LED 314, and thence from the collector to the emitter o transistor 320. ~ence, the green LED i5 lit ~o indicate the;battery is above thé predetermined voltage.
There will also be some current which goes through 360 ohm resistor 332.
When the battery voltage is less than the predetermined voltage, which is basically established by Zener diode 322, the Zenar diode switches off thereby turning transistors 318 and 32~ o. Hence, current through green LED 314 is turned off. The current path from positive battery terminal 324 to the negative`ba~tery terminal is now through 360 ohm resistor 334, red LED 316 and resistor 332.
Alternat.ively, circuitry for indic\ting the status of ~he ;.,, I
. 1 ~4~6 power so~rce 12 is shown in Fi~3ure 17. This circuitry not only provides indications of the power source status but it also turns off the current to desolderer lO whenver the battery voltage falls below a predetermined level. In particular, a green light is lit lf the battery is charged above a first predetermined voltage and is fully operational, an amber light is lit if the battery has discharged below the first predetermined voltage and if a predetermined number of ampere hours are left before a cut-off signal and a red light is lit if the battery has discharged below good operating level whereby power will be removed from desolderer lO or whatever power utilization device is ~eing employed.
In Figure 17, Zener diode 340 determines the voltage which separates the green light condition from the amber light condition. In the amber light condition, the battery should be recharged but still may be used for a limited amount of tlme.
The Zener diode 340 voltage is approximately about lO volts.
When the battery voltage is more than this voltage plus the base to emitter voltage of Lransistor 342, a current flows through lO0 ohm resistor 344, Zener diode 340 and through the base emittar junction of transistor 342. Thus, a current path is established through saturated transistor 342 from positive battery terminal 324 through green LED 346 J resistor 348 to the negative ba~ery terminal 328. When the voltage o~ power source 12 is less than about 10.5 volts, the current :through Zener diode 340 will substantially decrease thereby switching transistor 342 off. Point 350 will then go approximately to the battery voltage and green LED 346 will turn off. Diode 352 -2~-~5~6 will allow point 354 to be dekermined by the current through resistor 356 and amber LED 358 so that LED 358 is now turned on.
Zener diode 360 should have its knee about l to l-l/2 volts below that of Zener diode 340. At any voltage above the Zener voltage plus the base to emitter iunction voltaye of transistor 362, transistor 362 will be turned on. Transis-tor 362 supplies base current for a transistor 364 which, in - turn, controls the current through the heating element of desolderer lO. When the battery voltage drops below the Zener knee of diode:360, transistor 362 is cut off which, in turn, cuts off transistor 364 so that no further power can ba drawn . from the battery. Thus, the current path from positive battery . terminal 324 is switched through resistor 366 and red LED 368.
The circuitry of Figure 17 also includes 50 ohm resistor 370, 750 ohm resistor 372, 500 ohm resistor 374, 20 ohm resis-tor 376, diode 378 and 750 ohm resistor 380.
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' `' . .'"'' '' " ' I
..... ...... .
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. ~" ' ` ''`''' ' . I
-2~-
The desolderer described in this patent is suitable for many applications. However, where portability of repair equipment is desirable, the desolderlng tip should preferably be-quickly raised to the required desoldering temper- ¦
ature. ~owever, the available power supply may be relatively small ~a 12 volt battery, for example) so that the temperature can not be quickly raised by power alone. Also, there are other considerations which preclude the use of power alone to quickly raise the tip temperature. In any event, the efficiency of the desolderer in converting electrical energy to heat s~ould also be improved to permit the more efficient utilization of a smaller power supply.
Thus, for the above reasons, it is desirable that the ratio o~ the hea~ capacities ~or masses) of bobbin 87 and tip 78 be substantially less than that employed in U. S. Patent 3,392,897.
Generally, the heat capacity (or mass) of the bobbin should not be more than approximately twice that of the tip~
.1 The rea:rward portion of bobbin 87 is preferably outwardly I bent as indiaated at 114 to thereby mechanically hold the heater assembly together and to also assist in the sealing o~ the vacuum.
,' ' ' -10-, . I
~1~5~16 The forward end 117 of handle 82 is èxternally threaded at 118. An internally threaded cap 120 is threaded onto threads 118 to removably secure the flange 106 of heater assembly 80 to handle 82. Thus, due to the removable connection of the heater assembly to the handle, the heater assembly can be readily removed for repair or replacement. The forward end 117 of handle 82 is rectangularly slotted at 122 as indicated in Figure 6 to receive the rectangular flange 106 of heater assembly 80 in mating engagement. Hence, the heater assembly is non-rotatably mounted with respect to the handle 82.
The opposite ends of heating wire 110 are connected to flat electrical contacts 124 (typically nickel), which may pass between flanges 106 and spacer 108, there preferably being pro~ i l vided channels on the inner surfaces of the flanges to facili-1 15 tate tha passage of the contacts between the flanges and the spacer. The contacts 124 are then bent against the rear faces of flanges 124 and finally are bent once again into holes 125 in the rear faces to secure them in place.
Contacts 124 engage contacts 126 (beryllium, for e~ample) provided at the forward end of handle 82, which contacts may be J-shaped to provide some springiness and thus intimate contact I with contacts 124. The forward end 117 of the handle may be provid~d with slots into which contacts 126 may be inserted and held in place, the contacts 126 terminating at 128.
The forward end of solder collec~ion chamber 84 is pressed against a flexible seal 146 disposed within forward end 117 of the handle. The seal 146 intimately fits over contacts124 to provide an hermetic seal at the points where the contacts pass to the space outside solder collection chamber 84. In this connection, it.shouId be noted the forward end of solder collec-tion chamber.84.is effectively connected to sleeve 102 via seal 146 and flange 106.. Hence, the foregoing arrangement provides a novel and advantageous technique or connecting the heater wires to the space outs:Lde cham~er 84 when the chamber is mounted with respect to a sleeve (sleeve 102) which contains the heater wires. Xence, thermal isolation of seal 146 rom tip 78 is enhanced thereby promoting seal performance and longevity. ~lso, by moving annular rear spacer 108 to the right in Figure 3, the thermal isolation of the seal can be furthcr enhanced.
It should also be noted with respect to seal 146 that not only does one.side thereof seal the connection of the heater wires.to the outside of chamber 84, but the other side ~hereof . seals the forward end of the cha~.~er. Hence, the seal is doubly effective in maintaining the requisite vacuum space withir.
1 the desolderer. .
i Wires 130 are connected to points 128, the wires passing , 20 through a cable 132 back to porta~le power pack 42 of Figure .~ 2. A light emitting diode 134 mounted on handle 82 is con-nected across wires 130, the purpose of which is to in-. dicate to the operator that the desolderer ls ready for . use as will be described i~ more detail hereinafter with respect to Figure 16.
Also extending through cable 132 are wires 136 which engaSe .1 ' . . . ' . , ' 'i ~ 12- ' ,' .. , ''.
.. .. ..
~5~6 ..
flexible contact 138 and contact 140, as can be seen in Figure 3.
A push button 142 engages flexible contact 138 and is normally outwardly biased by a spring 144. Upon depression of spring 142, contacts 138 and 140 are closed to apply vacuum or pressure to the desolderer as indicated in Figure 2. As can be seen in Figures 3 and 7, a plurality of ribs 148 depending from the inner surface of handle 82 center and support solder collec-tion chamber 84.. As can also be seen in Figure 7, handle 82 , is provided with a hollow ridge 150 which provides for the mounting of LED 134, switch 142, contacts 138 and 140 and 1. which provides a passageway for wires 130 and 136.
I . As stated above, collection chamber 84 is pressed against . forward seal 146. This is effected by a spring loaded rear . housing 86, as can best be seen in Figures 3, 8 and 9. This housing comprises an air/vacuum tube 152, the rearward end of which has hose 72 disposed thereover and the forward end of which has a helical baffle 154 connected thereto by means of . a set screw 156. A hole 158 extends through ~he tube from hose 72 to an opening 160 extending through the side of the tube. Thus, an air/vacuum path is established ~rom the interior . of chamber 84 to hose 72. Tube 152 is mounted with respect to chamber 84 via a cup-shaped seal 162 having a forward portion 164 which extends into chamber 84 to provide an air-tight seal and an enlarged rear portion 166 which fits over the end ~ ~of chamber 8 A ring 168 may be provided OA the outer .1 . I
., Y13-' ' !' i ~4~ 6 . circumference of tube 152 to position the tube with respect to seal 162. , Slidably disposed on tube 152 is a detenting pinch lock 170, the purpose o which is to hold chamber 84 in place within handle 82 in a press fit against forward seal 146. The locX
170 is generally H-shaped and includes a cylindrical bearing . hub 172 which is slidably disposed on tube 152. Extending from hub 172 are a pair of flexible support arms 174 which . support a pair o flexible, gripping fingers 176, The forward ends of ~ingers 176 are provided with detents 178. A com-pression spring 180 is mounted around tube 152 between the rearward portion 166 of seal 162 and arms 174 of lock 170.
Thus, the lock is normally biased away from the rearward end of chamber 84. A ring 182 mounted on tube 152 limits the rear ward movement of lock 170.
In order to pro~ide a gripping surface for detents 178 of lock 170, ,a pair of openings 184.are provided in the sides of handle 82., The rear edge 186 of these openings provides the requisite-gripping surface. Also, as can best be seen in Figures 8 and 9, a pair of lands 188 are provided on the rear- If ward surface of handle 82 to provide a pair of recesses upon l, which the fingers 176 may be mounted. 1, ~he~ the spri~g loaded rear housing 86 is in the position ~ shown in Fi~ures.3 and 8, the solder collection chamber 84 is locked into position within the handle 82 and is ready for operation. Assuming the heater has been en~rg;ze~, the o~er~or ne~d only ~ress b~tton 142 whereby vacuum may be applied to tip 78, to withdra~ molten solder through tip 78 into solder ~ 6 collection chamber 84 where it splatters against helical baffle 154. Due to the helica.l shape of the ba,fle and due to the placement of vacuum port 156 on the side of tube 152, there is little, i any, probability o the molten solder entering the por~. After a number of operations, it will be-come necessary to clean chamber 84 of the molten solder col- ¦
lected therein. This is simply effected by pinching the fingers 176 of lock 170 to the dotted line positions shown in Figure . 8. Once the detents 178 are removed fxom edges 186 of openings 184, spring 180 will push lock 170 back to stop 182. Thus, the entire assembly including spring loaded rear housing 86 and solder collection chamber 84 may be removed from the open rearward end of handle 82. Once this is done, the seal 162 may be removed from chamber 84 thereby removing the entixe rear housing 86 from the chamber. As the housing is removed from the chamber, it may be rotated by the operator to thereby scrape the inner surface of chamber 84 with the edges of the helical baffle 154 and thus scrape ~he surface clean of any solder solidified thereon. To expedite this, the radial extent-of the baffle .154 substantially corresponds to that of the inside diameter of collection chamber 84 as can be seen in Figures 3 and 8.
Once the cham~ber has been cleaned, it can again be mounted on the forward portion 164 of seal 162. The entire assembly is then inserted into the handle with the lock 170 being pinched to its.dotted position as shown in Figure 8. The assembly including rear housing 86 and chamber 84 is then pressed against spring 180 until detents 178 can b~ detented over 1 ~ 54~
the edges 186. At this time the lock 170 is released to thereb~
once again lock the collection chamber 84 in place within handle 82 and press fit the forward end of the chamber against forward seal 146 and thus, effect an air-tight seal at this end of the charber. It should be noted from the above that rear housing 86 is advantageously moved straight in and out when it is attached and disconnected from the handle. Further, in Figure 9 ribs 1~8 are also provided at the rearward end of handle 82 to provide additional centering support for the chamber within the handle.
Also the rearward end of handle 82 is open as indicated at 183 in Figures 3 and 9 to provide air venting thxough opening 183 and side openings 184 to thereby promote heat dissipa~ion from solder collection chamber 84.
Referring now to Figures 10-12, there is shown an illus-1~ trative vacuum pump in accordance with the invention. Motor 18 for driving pump 16 is commercially available, it typically being a 12 volt DC motor which is available, for example, from the Pittman Company, ~arleys-~ille, Penna. The drive shaft 190 has mounted thereon a rotor 192, the shaft being provided with a key-194 which engageR a slot 196 within the rotor. The rotor-can ~e powdered metal or extruded or molded plastic.
Provided within the xotor are four slots which slidably receive four vanes 198. The vanes may be made from a lower cost phenolic or carbon. A rotor housing 200 is eccentrically mounted with respect to rotor 192, the housing being mounted via screws 202 to a plate 204 non-rotatably mounted onto ro~or 18. A rotor end plate 206 is disposed between the housing 200 and plate 204. Recesses 208 are provided in housing 200 so that the heads of screws 202 are recessed within the housing.
A further rotor end plate 210 is disposed between housing 200 ~ !'.7!r~
~.:3 45~16 and a plate 212. Plate 212 is secured to plate 204 via screws 214 to thereby,hold the pump together.
.As can be seen in Figure 11, the inner surace of housing 200 is provided with an elongat:ed indentation 216 at the edge thereof,adjacent end plate 210. Further, the inner surface is also provided with a further indentation 218 which is also adjacent the end plate 210. Thus, when the rotor is rotated in the clockwise direction in Figure 11, the sliding vanes 198 will assume the illustrated positions and will create a vacuum,at indentation 216 and air under pressure at indenta-tion 2,18. As can be seen in Figures 11 and 12, a pair of tubes 220 and 222 are mounted on plate 212 and are in alignment with holes ,224 which extend through plate 212. Further, these holes.are in,alignment with indentations 216 and 218 of the rotor. Hence, vacuum is provided at port 220 and air under pressure at port 222.
..The vacuum/pressure pump of Figures 10-12 in combination with motor 18.has.a number of op'erational and structural ad-vantages. ,Operationally, the pump is run at a speed much higher than would be normally required to ~enerate the vacuum : needed by desolderer 10. In particular, it is typically run at 8,,000 RP~. By running the pump at this high speed, it is : possible to generate the requisite vacuum in spite of the small size of the pump - that is, typically 1~ inches or less in diameter and:l-1/2 inches or less in length. Further,. by running the pump at a high speed, it is not necessary to . accurately ~abricate the pump components to close tolerances.
This~ in tur~ results in a very economical pump and thereby . -17-.
ll ~ 5~6 lessens the overall cos-t of the portable repair system of this invention. Thus, in fabricating the pump, costly and time consuming rotor shi~ing operations are eliminated. Further, the rotor, rotor housing and vanes can be finished ground in S one pass. Also to further reduce assembly time and facllitate 1, field service without special t:ools, the rotor and vanes are self-centered and self-sealed. To compensate for any tendency of housing 200 to heat as the pump is driven at the high speed, housing 200 is preferably provided with a plurality of circumferentially disposed fins 201, which may be formed during the extrusion of ~he housing.
As can be,seen in Figures 2 and 10, hoses 230 and 232 are respectively connected to vacuum and pressure tubes 220 and 222 where hose 232 is connected to connector 66 and hose 230 is connec,ted to one side of filter 60. A hose 234 is con-nected to the other side of filter 60 and at its other end to connector 68., Referring to Fi~ures 13-15,~an illustrative filter 60 is shown. As can be seen in Figure 13, hose 232 is connected to a first cup-shaped member 236 comprising a first part of filter 60 and as can be seen in Figure 14, hose 234 is connected ~o a second cup-shaped member 238. As can be seen in Figure 15, cup-shaped member. 238 is adapted to receive at least one porous ilter 240 and a further ~ilter 242 i~ desired. Further, member 236 is adapted to recelve a gasket 237 and member 238 after the , , latter member has been loaded ~ith filter material. Both members I
236 and 238 are made of flexible material to facilitate the engagement o~,member 238 by member 236. As can be seen in .1 . . Il, ~, . ' . '~
, -18~
., ,,, ~s~
l~
Figures 13 and 15, member 236 is provided with a ci~cumferen~lal ridge 244 at the lower opening 246 thereof which holds member 238 in place`after lt has been inserted within member 236.
To facilitate the engagement of member 238 by member 236, member 238 is~ also provided with an inwardly slanted outer peripheral wall 248.
To re-tain the filters 240 and 242 in place, member 236 is provided with a further circumferential ridge 250 which is so disposed às to engage the filters and hold them in place as indicated in-Figure 15. The flexible material of which the members 236 and 238 are made is preferably a transparent plastic whereby the condition of filters 240 and 242 can be readily observed, as indicated in Figure 2, to thereby ensure filter-replacement when necessary. Due to the two-piece con~
` 15 struction o the filter container 60, member 238 can be readily snapped from member 236, new filters inserted, and snapped back together in an expeditious manner.
Referring to Figure 16, there is shown illustrative temperature`control/ battery status circuitry 14. The cir-cuitry for controlling the heating current to and thus the temperature of heating element 110 of Figure 3 is such that the heating current is supplied at a high rate when the hea~ing element is below a selected temperature and at a very low rate when it is above the selected temperature. The material emplo~ed fox heating element 110 has a positive temperature coefficient of resistance and typically varies from about 1 ohm when cold to`about 4 ohms when the maximum temperature has been reached, alt:hough, o course, other resistance ranges may be ll .' ~454~6 ll utilized. Typically, the heater element material ma~ be a nickel-iron alloy. The circuitry of Figure 16 senses the change in resistance by sensing the change in current through the heating element to thereby control its temperature. A ', digital system as opposed to an analog system is employed to thereby lessen power consumption. Accordingly, pulsed power is continuously applied to element 110 to obtai~ samples of the heater temperature. The sampling is effected by an oscil-lator comprising a comparator 254, a lOK resistor 256, a diode 258, a .027 microfarad capacitor 260 and a voltage divider comprising a 1 megohm resistor 262 and a lOOK resistor 264, it being understood ~he foregoing values are for purposes of illustration.
When heater 110 is raised to its selected temperature, comparator 254 turns off so that its output goes positive.
This allows the capacitor to charge through resistors 262 and 264. As capacitor 260 charges positively, the inverting input of comparator 254 becomes more positive, When it be-comes more positive than the non-inverting input, the outpu~
of comparator 254 goes to ground thereby discharging capacitor 260 through resistor 256 and diode 258, the discharge time being much faster than the charging time.
During the time capacitor 260 is discharging, the output of comparator 254 remains at ground. ~his causes the non-inverting input of a comparator 266 to be at ground while the inverting input thereof is fixed at typically about 4 volts. I
Accordinglyl the output of comparator 266 is grounded. This, ~! in turn, causes a transistor 268 to be cut off. Accordingly, ~I
~20-, ~ . .
~5~16 current flowing through a 200 ohm resistor 270 no longer flows into the base of a transistor 272 where transistors 272 and 274 comprise a Darlinyton pair which supply current to heating element 110.
If the temperature is high enough so that the inverting input to a comparator 276 remains helow the input setting at the non-i~verting input thereof, the sampliny of the heater temperature will last only until capacitor 260 is discharged.
The input settiny at the non-inverting input o comparator 276 may be controlled by a potentiometer 278 or it may be fixed by 27K resistor 280 and 1~ resistor 282. If, as stated above, the temperature is high enough so that the inverting input to comparator 276 remains below the non-inverting input setting, the inverting input of comparator 254 will become ~egative and the output will go positive and capacitor 260 will again start charging positive through resistors 262 and 264. The diode 258 prevents positive charging through resistor 256 on the output o~ comparator 254.
If the temperature is low, the sampling current will ~e high due to the low resistance of heater element 110. Thus, the inverting input of comparator 276 will be more positive than the non-inverting input thereof and the output will be grounded.
This will cau e the non~inverting input o comparator 254 to be more nega~ive and the output of comparatox 254 will stay negative. Hence capacitor 260 will not charge positive as long as the inverting input of comparator 276 is more positive than the non-inverting input.
As the temperature of heating element 110 increases its ~54~
resistance.increases and the current decreases. Eventually, the inverting input of comparator 276 will become negative wit'.
respect to the non-inverting input and the outpuk will move positive. This will allow comparator 254 to switch so that its output will be positive and the capacitor will again charge positive. Also, comparator 266 will switch so that its output will become positive and turn on transistor 268 so that the power pair 272 and .274 are turned off and no current is supplied to heating element 110. After capacitor 260 is charged to thereby switch comparator 254, another sample will occur and the cycle is repeated.
As can be appreciated, the current through heating element 110 is not switched on and of until the current reaches the input setting established at the non-inverting input of com-15 parator 276... Hence, LED 134 of Figures 3 and 16 is not switched on and off until the heating element has been raised to its operating temperature. Accordingly, the operator is notified when the desolderer is ready for use by the blinking on and ofi-of LED 134. Although shown conveniently mounted on the handle of the desolderer in Figure 3, LED 134 can also be mounted on the front panel of the portable power pack shown in Figure 2A.
Other elements employed in the temperature controller circuitry of.Figure 16 are a .1 resistor 28~, 2~ resistor 286, . 200K resistor 288, lOOK resistor 290, comparator 292, lOK
resistor 294,.lOK resistor 296, lOOK resistor 298, lOK resistor 300, diode 302, lOK resistor 304, lOOK resistor 306, lOOK
resistor 308 and 200K resistor 310, it again being understood ~he foregoing.values are given for purposes o~ ill.ustratlon.
.
. -2~- .
.' ~.
~ 5~6 The battery s~atus circuitry of Figure 16 employs a single bulb or package 64 (also see Figure 2) containing two LEDs 314 and 316 which indicate whether the battery voltage is above ~green LED 314 on, red LED 316 off) or ~elow (red ~ED 316 on, green LED 314 off) a certain pre~etermined voltage. The pre-determined voltage is determined by the base to emitter voltage (ON) of two transistors 318 and 320 plus the Zener knee voltage of a Zener diode 322. When the battery voltage is higher ~han the predetermined voltage, a current path is from the positive battery terminal 324 through the emitter-base junction of transistor 318, through Zener diode 322 and 180 ohm resistor 326 into the base of transistor 320 and out its emitter to negative battery terminal 328. Thus, transistors 318 and 320 saturate and a further current path is established b~tween the emitter and collector of transistor 318, through 180 ohm resistor 330-, green LED 314, and thence from the collector to the emitter o transistor 320. ~ence, the green LED i5 lit ~o indicate the;battery is above thé predetermined voltage.
There will also be some current which goes through 360 ohm resistor 332.
When the battery voltage is less than the predetermined voltage, which is basically established by Zener diode 322, the Zenar diode switches off thereby turning transistors 318 and 32~ o. Hence, current through green LED 314 is turned off. The current path from positive battery terminal 324 to the negative`ba~tery terminal is now through 360 ohm resistor 334, red LED 316 and resistor 332.
Alternat.ively, circuitry for indic\ting the status of ~he ;.,, I
. 1 ~4~6 power so~rce 12 is shown in Fi~3ure 17. This circuitry not only provides indications of the power source status but it also turns off the current to desolderer lO whenver the battery voltage falls below a predetermined level. In particular, a green light is lit lf the battery is charged above a first predetermined voltage and is fully operational, an amber light is lit if the battery has discharged below the first predetermined voltage and if a predetermined number of ampere hours are left before a cut-off signal and a red light is lit if the battery has discharged below good operating level whereby power will be removed from desolderer lO or whatever power utilization device is ~eing employed.
In Figure 17, Zener diode 340 determines the voltage which separates the green light condition from the amber light condition. In the amber light condition, the battery should be recharged but still may be used for a limited amount of tlme.
The Zener diode 340 voltage is approximately about lO volts.
When the battery voltage is more than this voltage plus the base to emitter voltage of Lransistor 342, a current flows through lO0 ohm resistor 344, Zener diode 340 and through the base emittar junction of transistor 342. Thus, a current path is established through saturated transistor 342 from positive battery terminal 324 through green LED 346 J resistor 348 to the negative ba~ery terminal 328. When the voltage o~ power source 12 is less than about 10.5 volts, the current :through Zener diode 340 will substantially decrease thereby switching transistor 342 off. Point 350 will then go approximately to the battery voltage and green LED 346 will turn off. Diode 352 -2~-~5~6 will allow point 354 to be dekermined by the current through resistor 356 and amber LED 358 so that LED 358 is now turned on.
Zener diode 360 should have its knee about l to l-l/2 volts below that of Zener diode 340. At any voltage above the Zener voltage plus the base to emitter iunction voltaye of transistor 362, transistor 362 will be turned on. Transis-tor 362 supplies base current for a transistor 364 which, in - turn, controls the current through the heating element of desolderer lO. When the battery voltage drops below the Zener knee of diode:360, transistor 362 is cut off which, in turn, cuts off transistor 364 so that no further power can ba drawn . from the battery. Thus, the current path from positive battery . terminal 324 is switched through resistor 366 and red LED 368.
The circuitry of Figure 17 also includes 50 ohm resistor 370, 750 ohm resistor 372, 500 ohm resistor 374, 20 ohm resis-tor 376, diode 378 and 750 ohm resistor 380.
:. . ~~ ' ' i.
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. ~" ' ` ''`''' ' . I
-2~-
Claims (10)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A desolderer comprising a tubular sleeve;
a heating wire disposed within said sleeve;
a hollow handle, said tubular sleeve being mounted on the forward end of said handle;
a tubular solder collection chamber disposed within said handle and adapted for connection to a vacuum source;
a tubular desoldering tip heated by said heating wire and communicating with said tubular solder collection chamber through said tubular sleeve to thereby facilitate the passage of molten solder from the tip to the collection chamber;
a seal disposed between said solder collection chamber and said tubular sleeve; and electrical connecting means adapted to connect said heating wire to a source of electrical energy, said electrical connecting means being in contact with one side of said seal as the electrical connecting means extends from the inside of said tubular sleeve to the outside of said solder col-lection chamber.
a heating wire disposed within said sleeve;
a hollow handle, said tubular sleeve being mounted on the forward end of said handle;
a tubular solder collection chamber disposed within said handle and adapted for connection to a vacuum source;
a tubular desoldering tip heated by said heating wire and communicating with said tubular solder collection chamber through said tubular sleeve to thereby facilitate the passage of molten solder from the tip to the collection chamber;
a seal disposed between said solder collection chamber and said tubular sleeve; and electrical connecting means adapted to connect said heating wire to a source of electrical energy, said electrical connecting means being in contact with one side of said seal as the electrical connecting means extends from the inside of said tubular sleeve to the outside of said solder col-lection chamber.
2. A desolderer as in Claim 1 where said seal engages said tubular sleeve and where said electrical connecting means includes at least one electrical contact disposed on said tubular sleeve at the point where said seal engages said tubular sleeve, said one electrical contact being connected to one end of said heating wire.
3. A desolderer as in Claim 2 where said electrical connecting means includes a further electrical contact disposed between said tubular sleeve and said seal, said further electrical contact ex-tending to the space outside said solder collection chamber.
4. A desolderer as in Claim 1 including a tubular heating wire support means for supporting said heating wire where said tubular desoldering tip includes a circumferential protuberance and said heating wire support means includes a circumferential groove pro-vided on an internal surface thereof for receiving said circumferential protuberance of the desoldering tip so that said tip may be removably positioned with respect to the tubular sleeve.
5. A desolderer as in Claim 4 where said groove in the heating wire support means comprises a counterbore in the forward edge of said tubular sleeve.
6. A desolderer as in Claim 4 where said groove is removed from the forward edge of said heating wire support means.
7. A desolderer as in Claim 6 where said heating wire support means has at least one longitudinal slot extending from the forward edge thereof to permit said desoldering tip with its protuberance to be inserted into said support means.
8. A desolderer as in Claim 4 where said handle is hollow and said solder collection chamber is disposed within said handle, said protuberance further acting as a seal between the tip and the heating wire support means.
9. A desolderer as in Claim 1 where said seal is annular and planar and where said solder collection chamber engages the side of said seal opposite said one side.
10. A desolderer as in Claim 9 including spring biasing means for biasing said solder collection chamber toward said opposite side of the seal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000352033A CA1145416A (en) | 1980-05-15 | 1980-05-15 | Portable electronics repair system including improved desolderer for use therewith |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000352033A CA1145416A (en) | 1980-05-15 | 1980-05-15 | Portable electronics repair system including improved desolderer for use therewith |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1145416A true CA1145416A (en) | 1983-04-26 |
Family
ID=4116959
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000352033A Expired CA1145416A (en) | 1980-05-15 | 1980-05-15 | Portable electronics repair system including improved desolderer for use therewith |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1145416A (en) |
-
1980
- 1980-05-15 CA CA000352033A patent/CA1145416A/en not_active Expired
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| Date | Code | Title | Description |
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| MKEX | Expiry |